Animals such as mammals and birds are often susceptible to parasite infestations. These parasites may be ectoparasites, such as insects, and endoparasites such as filariae and worms.
Farm animals are particularly susceptible to parasite infestations, which can be associated with illness and death or reduced productivity. For example, cattle are affected by a large number of parasites. An example includes the parasitic trematode, Fasciola hepatica or common liver fluke. F. hepatica is an important trematode of domestic ruminants and is the most common cause of liver fluke disease in temperate areas of the world. Migration of flukes in the liver damages the tissue, resulting in formation of scar tissue, disrupting normal liver function and decreasing albumin production. Flukes also ingest red blood cells directly, causing iron-deficiency anemia if the animal's iron stores are exhausted by replacing lost cells. The combination of these conditions over a prolonged period causes decreased growth, weight loss, anemia, and edema. Liveweight gain and milk production can be reduced by up to 8% in moderately infected cattle. Economically important infections are seen in cattle and sheep in three forms: chronic, which is rarely fatal in cattle but often fatal in sheep; subacute or acute, which is primarily in sheep and often fatal; and in conjunction with “black disease” (infectious necrotic hepatitis), which is most common in sheep and usually fatal.
Animals and humans also suffer from endoparasitical infections including, for example, helminthiasis which is most frequently caused by a group of parasitic worms described as nematodes or heartworms or roundworms. These parasites cause severe economic losses in pigs, sheep, horses, and cattle as well as affecting domestic animals and poultry. Other parasites which occur in the gastrointestinal tract of animals and humans include Ancylostoma, Necator, Ascaris, Strongyloides, Trichinella, Capillaria, Toxocara, Toxascaris, Trichuris, Enterobius, Ostertagia, Haemonchus, Trichostrogylus, Cooperia, Nematodirus, Chabertia, Oesophagostomum, Bunostomum and parasites that are found in the blood or other tissues and organs such as filarial worms and the extra intestinal stages of Strogyloides, Toxocara and Trichinella. 
Also, a parasite which is very prevalent among farm animals is a tick genus Boophilus, especially those of the species microplus (cattle tick), decoloratus and anulatus. Ticks, such as Boophilus microplus, are particularly difficult to control because they live in the pasture where the farm animals graze. Other important parasites of cattle and sheep are listed as follows:
myiases such as Dermatobia hominis (known as Berne in Brazil) and Cochlyomia hominivorax (greenbottle); sheep myiases such as Lucilia sericata, Lucilia cuprina (known as blowfly strike in Australia, New Zealand and South Africa). These are flies whose larva constitute the animal parasite;
flies proper, namely those whose adult constitutes the parasite, such as Haematobia irritans (horn fly);
lice such as Linognathus vitulorum, etc.; and
mites such as Sarcoptes scabiei and Psoroptes ovis. 
Likewise, domesticated animals, such as cats and dogs, are often infested with one or more of the following ectoparasites:
cat and dog fleas (Ctenocephalides felis, Ctenocephalides sp. and the like),
ticks (Rhipicephalus sp., Ixodes sp., Dermacentor sp., Amblyoma sp. and the like), and
mites (Demodex sp., Sarcoptes sp., Otodectes sp. and the like),
lice (Trichodectes sp., Cheyletiella sp., Lignonathus sp., and the like),
mosquitoes (Aedes sp., Culex sp., Anopheles sp., and the like) and
flies (Hematobia sp., Musca sp., Stomoxys sp., Dermatobia sp., Cochlyomia sp., and the like).
Fleas are a particular problem because not only do they adversely affect the health of the animal or human, but they also cause a great deal of psychological stress. Moreover, fleas are also vectors of pathogenic agents in animals, such as dog tapeworm (Dipylidium caninum), and humans.
Similarly, ticks are also harmful to the physical and psychological health of the animal or human. However, the most serious problem associated with ticks is that they are the vector of pathogenic agents, agents which cause diseases in both humans and animals. Major diseases which are caused by ticks include borrelioses (Lyme disease caused by Borrelia burgdorferi), babesioses (or piroplasmoses caused by Babesia sp.) and rickettsioses (also known as Rocky Mountain spotted fever). Ticks also release toxins which cause inflammation or paralysis in the host. Occasionally, these toxins are fatal to the host.
Moreover, mites and lice are particularly difficult to combat since there are very few active substances which act on these parasites and they require frequent treatment.
The above list is not exhaustive and other ectoparasites are well known in the art to be harmful to animals and humans. These include, for example, migrating dipterous larvae.
Endectocidal compounds, which exhibit a degree of activity against a wide range of endoparasites, are known in the art. These compounds possess a macrocyclic lactone ring and are known in the art to be particularly effective against ectoparasites, including lice, blowflies, flies, mosquitoes, mites, migrating dipterous larvae, and ticks, as well as endoparasites, such as nematodes, heartworms and roundworms. Compounds of this group include avermectins, milbemycins, and derivatives of these compounds, for example, abamectin, doramectin, emamectin, eprinomectin, ivermectin, latidectin, lepimectin, milbemectin, moxidectin or selamectin. Such substances are described, for example, in U.S. Pat. Nos. 3,950,360; 4,199,569; 4,879,749; and 5,268,710.
While it is known in the art that it is sometimes possible to combine various parasiticides in order to broaden the antiparasitical spectrum, it is not possible to predict, a priori, which combinations will work for a particular animal or disease state. For this reason, the results of various combinations are not always successful and there is a need in the art for more effective formulations which may be easily administered to the animal and have the required solvency, stability and bioavailability. The effectiveness of formulations comprising flukicides, such as clorsulon, and macrolide lactone anthelmintic or parasitic agents, such as ivermectin and eprinomectin, against an endoparasite or an ectoparasite in a specific host is especially difficult to formulate because of the challenges in achieving the required solvency, stability and bioavailability.
Thus, there is a need in the art for antiparasitic formulations that meet the required solvency, stability and bioavailability of the parasiticides to be formulated therein.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.